【作者】 童丹；

【导师】 陈慧；

【作者基本信息】 西北师范大学 ， 分析化学， 2008， 硕士

【摘要】 近年来,随着工农业的迅速发展,环境污染和生态破坏日益严峻,严重影响到人类的生存和健康。其中土壤污染问题已经成为一个亟待重视和解决的问题。土壤中的污染物包括有机物、重金属、放射性物质和各种病原菌等。有机物污染是造成土壤环境质量下降的重要原因之一,许多有毒有机污染物常常持久性地存在于土壤,很难被土壤微生物降解而从土壤环境中去除,却可通过土壤和食物链进一步富集,造成土壤和作物的污染,对人类健康和生态环境具有很大的潜在危害。疏水性有机污染物(Hydrophobic Organic Compounds,HOCs)由于在水中溶解度很小,大多数以吸附态存在于土壤中,是具有长期性和潜在性的一类有毒有机污染物。随着外界条件的变化,也有一部分可以缓慢溶解进入水相,因而造成地下水和饮用水源的污染。通常,对含有疏水性有机污染物的土壤采用以下两种修复转化方式:(1)使疏水性有机污染物以吸附态固定在土壤表面,从而减小了它们的流动性;(2)使其分配进入流动相,增加在水中的溶解度。对于后者,现场表面活性剂增效修复技术(SER)就是一种经济和有效的修复方法,即利用增效试剂使疏水性有机污染物溶解进入水相,从而提高其生物可利用性,促进微生物降解,降低其对土壤的危害。因此对疏水性有机污染物在地下环境中的迁移转化以及可行的修复技术的研究已经成为许多学者研究的热点课题。本文比较研究了生物表面活性剂皂角苷和化学表面活性剂Triton X-100对非极性有机污染物如多环芳烃在水和土壤间分配的影响以及其对多环芳烃菲的增溶作用,同时还比较探讨了生物表面活性剂皂角苷和Triton X-100对几种极性有机物在黄土上吸附行为的影响,从而为土壤有机物污染的控制和土壤修复提供了一定的理论依据。第一章综述文中较为详细地介绍了我国土壤有机污染现状及危害,有机污染物在土壤中的迁移转化规律,以及有机污染物在水和土壤间的分配理论,土壤有机污染的治理技术。最后介绍了表面活性剂增效修复技术治理有机污染土壤,以及生物表面活性剂的性质和利用前景。共引用文献68篇。第二章生物表面活性剂皂角苷对菲和萘在水和土壤间分配行为的影响本章选用甘肃兰州西北师范大学院内的深层未受污染的黄土和产自新疆托克逊县的膨润土作为供试样品,以菲和萘为非极性有机物的代表,比较研究了皂角苷、Triton X-100以及二者的混合物对菲和萘在水和黄土及膨润土间分配行为的影响。结果表明,在所选择的表面活性剂中,皂角苷对菲和萘在水和土壤间的分配具有最强的增溶能力。在竞争吸附的作用下,随着加入的表面活性剂的量不同,菲和萘在水和土壤间进行分配行为也有差异。当表面活性剂的浓度较低时,促进菲和萘在土壤上的吸附;当加入的表面活性剂的量超过其临界胶束浓度(CMC)时,菲和萘在水和土壤间的分配系数随着表面活性剂浓度的增大出现持续减小的趋势。并且在相同浓度下,皂角苷和Triton X-100组成的混合表面活性剂的增溶能力比单独使用非离子表面活性剂Triton X-100强得多,并且,在混合表面活性剂的协同作用下,菲和萘在水和土壤间的分配系数随着表面活性剂浓度的增加出现持续减小的趋势。第三章生物表面活性剂皂角苷对土壤中菲的增溶作用本章以深层未受污染的黄土为供试样品,在试样中掺杂一定量的菲,然后用皂角苷作为增溶剂,讨论了其对黄土中的菲的增溶洗脱效果,并与常用的非离子表面活性剂TritonX-100和Brij35对菲的增溶效果进行了比较。结果表明,在水体系和在水/土体系中,皂角苷对菲的增溶效果均比TritonX-100和Brij35好。同时,皂角苷与TritonX-100和Brij35相比有更高的质量增溶比(SR)和胶束假相和水相的分配系数(Kmc)。在水体系中皂角苷的质量增溶比是TritonX-100的1.6倍,是Brij35的1.9倍;在水-土体系中皂角苷的质量增溶比是TritonX-100的1.3倍,是Brij35的2.6倍。第四章表面活性剂对极性有机物在黄土上吸附行为的影响本章研究了极性有机物苯酚和苯甲酸在黄土上的等温吸附行为,以及不同浓度的表面活性剂溶液中,苯酚和苯甲酸在黄土上的吸附。结果表明,苯酚和苯甲酸在黄土上的吸附符合线性吸附模型;不同浓度的皂角苷溶液中苯酚和苯甲酸在黄土上的吸附量小于其在Triton X-100溶液中的吸附量。皂角苷溶液的浓度对几种极性有机物在黄土上的吸附也有很大影响,低浓度时,促进了几种极性有机物在黄土上的吸附;高浓度时,则抑制极性有机物在黄土上的吸附。并且在两种表面活性剂存在下,苯甲酸的吸附量均大于苯酚的吸附量。更多还原

【Abstract】 In recent years, with the development of industry and agriculture, environmental pollution and ecological damage are very serious. They affect survive and health of people. And soil pollution is one of the most common problem and much need of recognition and settlement. There are mainly four kinds of soil pollution: hazardous organic compounds and biologic contamination, heavy metal-contamination, and radioactive substances. Hazardous organic compounds contamination is the important reason for degrading of soil quality, and many of them have disadvantages of biotic degradation and entire remove from soil, resulting in persistent existence of them in the surface of soil, easy to assimilate by crop, and transfer in food chain. When reached a high concentration, it can destroy the soil-plant system.The hydrophobic organic compounds (HOCs) sorbed on soils have very low aqueous solubility, they serve as a potential long-term source of contamination, slowly dissolving to form plumes of contaminant that can spread via groundwater flow into regions used for drinking water supply. Depending on particular side conditions, two complementary remediation alternatives are often considered: (1) HOCs sorption to an immobile phase that subsequently decreases HOCs mobility or (2) HOCs partitioning to a mobile phase that results in an increase in HOCs mobility in water. For the latter, in-situ surfactant-enhanced remediation (SER) which leads to the alternation of HOCs bioavailability, has been suggested as an economically and technically feasible remediation approach. At the same time, the widespread occurrence of HOCs in soil and groundwater has led to intensive studies of mobility and fate of these contaminants in subsurface environments and their remediation potential.In this thesis, the effects of bio-surfactant saponin compared with nonionic surfactant Triton X-100 on the partition of non-polar polycyclic aromatic hydrocabon compounds (PAHs) between aqueous phase and soil have been investigated. The solubilization of phenanthrene and naphthalene, and their distribution coefficients between aqueous phase and soil as well as the sorption behaviors of several polar organic compounds on loess soil in the presence of saponin and Triton X-100 have also been discussed in detail. The studies provide principles on the soil contamination control and remediation. Chaper 1.Summarize:Organic pollution and quality of biosurfactantIn this review with 68 references cited, detailed introductions have been given on the current situation of soil contamination by organic compounds in China, the transfer and transform of organic compounds in soil, the theory of organic compounds partitioning between aqueous phase and soil, and the remedial techniques of soil contamination. The applications of surfactants, especially bio-surfactants, in the remediation of contaminated soil have also been described.Chaper 2.Effect of biosurfactant (Saponin) on the distribution of phenanthrene and naphthalene between water and soilThe effects of saponin, Triton X-100 and their mixtures on the partition of phenanthrene and naphthalene between aqueous phase and loess or bentonite have been studied. Saponin exhibits the largest solubilization content among the selected surfactants. Phenanthrene and naphthalene distributions between the immobile and mobile phases varied with surfactant dose because of the competition between sorbed and micellar surfactants for PAH partitioning. The distribution coefficients decreased with increasing surfactant concentrations after the critical mucilage concentration (CMC) of surfactants. The solubilization by mixed saponin and Trinton X-100 were much larger than that by single nonionic one when the initial dosages of surfactants were the same.Chaper 3Solubility enhancements of phenanthrene by biosurfactant in loess soilThe uncontaminated loess samples were taken from the campus of Northwest Normal Chaper 1. University with certain amount of phenanthrene as artificial addition. When saponin was used as the solubilizer, phenanthrene adsorbed on loess was dissolved in the aqueous phase. The mechanism of this process was discussed. Two nonionic surfactants, Triton X-100 and Brij35, were compared with saponin and the result showed that saponin was a better solubilizer for phenanthrene than the others in both aqueous phase and aqueous-soil phases, with higher solubilization ratio (SR) and the micelle-phase/aqueous phase partition coefficient (Kmc). The obtained SR for saponin is higher 1.6 and 1.3 times than Triton X-100 in aqueous phase and aqueous-soil phase, respectively; and 1.9 and 2.6 times than Brij35, respectively.Chaper 4Effect of biosurfactant on sorption of polar organic compounds in loess soilThe sorption behaviours of phenol and benzoic acid on loess affected by saponin and TritonX-100 have been studied. The results showed that the sorption contents of the two compounds onto loess in presence of saponin were both smaller than those in presence of Triton X-100. The concentration of saponin had stronger influence on the sorption of polar organic compounds onto loess as well. The low concentration of saponin enhanced the sorption of organic compounds on loess, while the high concentration inhibited such sorption. Besides, the sorption contents of benzoic acid in saponin solution and in Triton X-100 solution were both larger than those of phenol under the same condition.更多还原